量子多址高斯信道的信息容量研究

Capacity of quantum multiple access Gaussian channel

与经典通信相类似,量子高斯噪声是一种重要的量子噪声模型.这里,"经典"是相对于"量子"而言的.讨论量子高斯信道传送经典信息时的信息容量,也称量子信道的经典容量,是量子通信的热点问题之一.文中在量子高斯态、高斯熵性质和Holevo界基础上,给出单用户量子高斯信道的经典容量,借助多址量子信道的经典容量区域定理,通过坐标系变换方法,从理论上推导得到多用户量子高斯信道的经典容量区域.为了计算简便且不失一般性,计算过程将采用两输入、单输出的量子多址信道模型进行说明,结论可类推到n个输入、单输出的多址信道.

As its classical counterpart,quantum Gaussian noise is an important noise model in quantum information theory. The study of capacity of quantum Gaussian channel plays an important role in quantum communications. Based on the definition of quantum Gaussian state,the entropy of quantum Gaussian state,and Holevo bound theorem,the classical capacity of quantum Gaussian channel is given at first in the paper,where the classical capacity is defined as the capacity when only classical messages are transmitted through the quantum channel. Then,the classical capacities of quantum multiple access Gaussian channels are deduced according to the classical capacity theorem of multiple access quantum channels. For simplicity and generality,a multiple access quantum channel with two senders and one receiver is used for computation. The results can be generalized to the quantum channel with n senders and one receiver.